The overall objectives of the EMS Research Program are a) to develop and apply evaluative methodologies to describe current modalities of emergency medical care and to assess the impact of interventions aimed at improvement and b) to examine the feasibility of a Health Services Research Center working collaboratively with two emergency departments in providing high quality evaluative data of management value in resolving operational and clinical decisions. The Research Program consists of three projects. Project I deals with system-wide interventions (such as regionalization upon patient utilization patterns) and is being conducted in the five-county Baltimore region. Project II focuses on health education and other service interventions introduced at the individual facility level and is based in the emergency departments of the Johns Hopkins Hospital and the Baltimore City Hospitals. Project III is concerned with clinical interventions and is also based at the emergency departments at the Johns Hopkins Hospital and the Baltimore City Hospitals.